This invention relates to a resin composition for artificial marble which can give a marble-like molded product having excellent water resistance, transparency and luster by compression molding under heating in a metal mold, a bulk molding compound or sheet molding compound using the same, and a process for preparing artificial marble using the same.
In the prior art, as a method of obtaining an artificial marble-like molded product, there have been known an injection molding method in which a radical polymerizable thermosetting resin compound is injected in a metal mold at a temperature of room temperature to about 80.degree. C. and a press molding method in which a sheet molding compound or bulk molding compound is subjected to compression molding by using a metal mold having a temperature of 100.degree. to 160.degree. C. at a molding pressure of 3 to 150 kgf/cm.sup.2.
In the former method, a molded product having relatively good transparency can be obtained, but there is a drawback that a molding cycle per one molded product is long. In Japanese Patent Publication No. 25928/1990, there has been disclosed a resin composition for injection molding which comprises a side chain-double bonded type polymer obtained by reacting a polymer having a glycidyl group at a side chain with acrylic acid or methacrylic acid, or a side chain-double bonded type polymer obtained by reacting a polymer having an acid anhydride group at a side chain with an unsaturated alcohol having an acryloyl group, a copolymerizable monomer and an inorganic filler. This composition has a low setting temperature of 60.degree. to 80.degree. C. so that it takes a long time to obtain a molded product and when a molded product which requires water resistance (e.g. a bathtub, a washstand and a kitchen counter) is prepared, it is necessary to form a gel-coated resin layer having water resistance.
Further, the side chain-double bonded type polymer used in Japanese Patent Publication No. 25928/1990 has a number average molecular weight of 5,000 or more so that compatibility with an unsaturated polyester resin is poor, whereby phase separation of said polymer is caused to lower characteristics of a molded product obtained.
In the latter method, a molding cycle is short and bulk productivity is excellent, but the compound contains a fiber reinforcing material or a resin such as a saturated polyester resin, polystyrene and polymethyl methacrylate as a low profile additive so that there is a drawback that transparency and stain resistance are poor.